Depends what coilovers you go for
From memory springs were £200ish & coilovers are arouns £1k.
The drop also depends on which coilover or spring as they lower different amounts
IMO the best offset to go for is between +20 & +25, Dont know about springs I went for coilovers
These are mine - 19", +22 offset lowered on cusco coilovers